Spaceflight History and Commentary

Cluster’s Last Stand: The Saturn I/1B

Few sights could be more synonymous with the space age optimism of the 1960s than the mighty Saturn V. Built to take Americans to the Moon at the culmination of a politically fuelled space race, it also represented the ultimate expression of von Braun’s long held desire to use rocketry to reach other worlds. But while the Saturn V is deservedly honoured for its historic role, much of the work to make this success possible was carried out during the development of its smaller, less well remembered predecessor – the Saturn I.

Often consigned to the footnotes of space history the Saturn I story began well before Apollo, the programme that provided its defining role. Saturn I’s early development spans the military power struggles of the pre-NASA age and indeed its development helped bring key capabilities to the nascent space agency that remain important and controversial to this day. Although understandably overshadowed by the mighty Saturn V, for a while it looked like the Saturn I and subsequent variants might become among the most important workhorses of America’s expansion into space, a flexible and ubiquitous launcher with a life way beyond the lunar landings. Unfortunately, as with so many of the ambitious plans of the 1960s, the Saturn I never fully realised this potential.

A new home at RedstoneThe genesis of the Saturn boosters really begins with the US Army’s decision to move the team of former Peenemünde rocket scientists and engineers headed by Wernher von Braun from their initial posting at Fort Bliss to a new location at the Redstone Arsenal in Huntsville, Alabama in 1950. A large workforce quickly built up around what now became the Ordnance Guided Missile Center (OGMC) and work began almost immediately on a new Short Range Ballistic Missile, the PGM-11 Redstone, which first flew from Cape Canaveral during August 1953.

During the development of the Redstone, many of the organisational concepts that would come to characterise the development of boosters at Huntsville developed. The in-house engineers would not only define the design of the vehicle but also fabricate and test the initial prototypes while training the contractor prior to turning final production over to them. This went against the usual Government client/contractor procurement relationship where a requirement would be issued to potential bidders who would then submit a design proposal and carry out all work if successful. Some observers felt this system gave the Huntsville team too much power – it was suggested that von Braun operated as a ‘managerial lord’, a criticism that would re-surface periodically over the coming years.

In 1956 the Huntsville team became part of the newly founded Army Ballistic Missile Agency (ABMA) under the command of General John Medaris. Work continued on the Jupiter-C (a three-stage IRBM derivative of the Redstone) which later launched the United States’ first satellite, Explorer 1 on January 31st 1958 in the Juno I configuration. As early as 1953 von Braun had suggested a programme to launch an artificial satellite and this idea had formed the basis of Project Orbiter, a joint Army/Air Force initiative that was overlooked by Eisenhower in favour of Vanguard. There was considerable frustration in Huntsville that, with the Air Force having been handed sole responsibility for the nation’s ICBM programme and the President seemingly unwilling to support an ostensibly military space programme, their talents were being wasted on short-range rockets. But while the honour of launching the first American satellite may have only come to them following the very public failure of Vanguard, von Braun had already begun to plan a larger space launch role for ABMA. During 1957 he submitted a proposal to the Department of Defence for ‘A National Integrated Missile and Space Vehicle Development Program’ using clustered engines and existing tankage to quickly create a large booster specifically designed for space launch, a concept that initially gained the in-house title ‘Super Jupiter’.

Enter ARPA, a new patron for the cluster… In the wake of Sputnik major changes were afoot as the Eisenhower administration looked for ways to formulate an appropriate American response to the perceived Soviet superiority in space. Two new organisations emerged from this process, both of whom would play significant roles in von Braun’s heavy booster plans. The Advanced Projects Research Agency (ARPA) formed in February 1958 with a remit to undertake advanced research and development projects for eventual military application. On July 29th 1958 the National Aeronautics and Space Act was passed, leading to the creation of the National Aeronautics and Space Administration (NASA) to oversee the civilian space and aeronautics research programmes.

Very quickly ARPA began to take an interest in von Braun’s Super Jupiter but whereas the ABMA team had proposed using a new engine, the Rocketdyne E-1, for the booster ARPA suggested utilising an upgrade to the existing Thor-Jupiter S-3D engine to reduce costs and development time. On the 15th August 1958 ARPA issued ABMA with an order to:

“Initiate a development program to provide a very large space vehicle booster of approximately 1,500,000 lb thrust based on a cluster of available rocket engines. The immediate goal of this program is to demonstrate a full-scale captive dynamic firing by the end of CY 1959”

Whilst the programme was now known as Juno V by the Huntsville team, this order was in effectively the birth of what would become the Saturn family.

An early concept of the Saturn C-1 showing a size comparison with existing ABMA boosters [IMG: NASA]Even with the financial support of the ARPA contract, funding was extremely tight during the early days of the programme with much of what was available going to Rocketdyne for the upgraded S-3D, now designated the H-1. The drive to reduce costs and timescales led the ABMA engineers to extend the clustering concept from the engines to the tankage. As the original ARPA contract simply required ABMA to demonstrate ‘dynamic firing’ on a test stand the decision was made to use a combination of lengthened smaller tanks from existing missiles rather than design and fabricate new large diameter tanks. The design that emerged used a single central 2.67 meter diameter Jupiter tank to hold the oxidiser surrounded by eight 1.78 meter diameter Redstone tanks, alternately filled with RP-1 refined kerosene and oxidiser to feed eight H-1 engines. The H-1s were arranged with a central cluster of four fixed engines surrounded by 4 gimballed outer engines to provide directional control. It was this somewhat inelegant but pragmatic configuration that earned the Saturn I the nickname ‘Cluster’s Last Stand’. Encouraged by progress at Huntsville, ARPA issued a memorandum in September 1958 extending the program to include flight tests within two years.

Structure of the S-1 stage (Block II shown here) Illustrating the clustered tanks and 8 H-1 engines [IMG: NASA]The progress on the new booster hadn’t gone unnoticed by NASA following its start of operations on October 1st 1958. The agency’s first administrator T. Keith Glennan had inherited a range of centres and laboratories from NASA’s predecessor the NACA, but now looked towards relevant military facilities to add to the space agency’s capabilities. ARPA’s big booster programme and von Braun’s group at Huntsville seemed a good fit for NASA, but while Glennan was quickly able to bring the Army operated Jet Propulsion Laboratory in Pasadena under the NASA umbrella, ABMA would prove more elusive. Even so, von Braun’s participation in the NACA initiated Stever committee meant that the big clustered booster began to figure heavily in NASA’s early plans and it seemed ABMA’s assimilation by the space agency was only a matter of time.

As debate continued as to the ownership of the Juno V project and the fate of the Huntsville team, attention turned to suitable upper stages for the new booster. In January 1959 the Rosen report, prepared by NASA for Eisenhower, suggested using the existing Atlas or Titan ICBMs as upper stages for the Juno V, but recognised that many of the proposed missions for such a booster would benefit from the increased lift that a liquid hydrogen powered upper stage such as the Centaur could provide. The Rosen report is also noteworthy for containing the first mention of a huge follow-on booster known as Nova which would utilise the F-1 engine, then under development by the Air Force.

NASA gets its rocket team at lastFebruary 1959 saw the Department of Defence officially drop the name Juno V in favour of Saturn, but soon the big booster ran into its biggest challenge to date – cancellation. In June 1959 the director of DoD research & Engineering, Herbert York, informed ARPA that the programme would receive no further funding, reasoning that continued support for Saturn risked diverting funds from higher priority projects and suggesting many of the DoD’s proposed missions could be achieved with existing boosters. Although this decision represented a huge blow to the military with their goals of orbiting large communications satellites, manned space stations and even developing the strangelove-esque atomic moon bases under Project Horizon – all of which relied to some extent on Saturn – it caused even greater alarm within NASA for whom Saturn represented the core of their ongoing desire for a national booster programme. Urgent meetings were convened to rally support for Saturn and following a series of discussions between the DoD, NASA and ARPA in September 1959 the programme was saved, but under the condition that both Saturn and its creators at the ABMA should be transferred to NASA making it a civilian rather than military programme. So York’s decision to cancel Saturn actually became the catalyst for the foundation of NASA’s in-house booster development capability, although there was some bad feeling on behalf of Medaris and von Braun who felt ABMA had been manipulated into NASA ownership. The transfer of employees and facilities in Huntsville was officially completed by July 1st 1960 when the Marshall Space Flight Center (MSFC) was formed with von Braun as its first director.

construction of an early S-1 stage. The central Jupiter tank is in place to the left. One of the smaller diameter Redstone tanks can be seen at the right of the image [IMG: NASA]While the political considerations of ownership were being settled during late 1959, the decision on which upper stage to use came into sharper focus via the activities of NASA’s Silverstein Committee. Recognising that the use of an existing ICBM for the upper stage of a new booster was an imperfect and largely inefficient solution, the committee recommended a new liquid hydrogen fuelled upper stage for Saturn, the S-IV, powered by 4 (although this later changed to 6) RL-10A-3 engines as used by the then-in-development Centaur and to be built by Douglas Aircraft. Finally, the Silverstein Committee proposed the development of a modular family of Saturn vehicles named C-1, C-2 and C-3. The C-1 would be a three stage booster featuring the clustered ‘Juno V’ S-1 first stage, the new S-IV second stage and a two engined S-V Centaur upper stage.

The S-IV Stage as carried on the Block II Saturn Is [IMG: NASA]With Saturn and its creators now an integral part of the organisation and a series of ever larger boosters planned, NASA could now look towards a 10 year plan that would include a moon landing by 1970. Eisenhower enthusiastically supported the development of the new, powerful launch vehicles giving Saturn a high-priority DX rating in January 1960. Project Apollo was announced as an advanced multi-crew follow-up to Project Mercury in July 1960 and while there was still conjecture as to which mission mode, and therefore which booster, would be used to reach for the Moon it was quickly recognised that the Saturn C-1 would have a key early role in proving technologies and testing equipment for Apollo.

Saturn SpaceplanesThe potential NASA lunar mission was not the only human spaceflight program for which Saturn was now being considered. As early as 1956 North American Aviation had submitted a proposal to the Air Force for sending an upgraded version of their X-15 rocket research aircraft into space. Initially the vehicle, named the X-15-B, was planned to ride on a cluster of booster rockets from another NAA project, the Navajo cruise missile. Post Sputnik, NAA revised their plans further proposing an orbital version of the X-15-B which could be launched on the Saturn C-1. As it was the Air Force decided that their quickest route to human spaceflight lay with a ballistic capsule and chose to pursue this direction under the Man In Space Soonest programme which laid the groundwork for what later became NASA’s Project Mercury. But while the X-15-B went no further the Air Force was still developing a more advanced spaceplane as System 464L and subsequently the Saturn C-1 became the subject of studies as a possible launcher for the resulting Dyna Soar spaceplane. Although still controlled by the Army when studies began, the booster seemed to offer a good solution for the Air Force vehicle, whose mission seemed ever-changing and weight was steadily increasing. Following the cancellation of initial plans for suborbital flights using a Titan I booster, Dyna Soar was now oriented to be a full orbital system and would need a more powerful booster. Discussions continued through the early years of NASA and the Kennedy administration but, as so often seemed the case with Dyna Soar, plans soon changed and it moved back to an improved version of the Air Force’s own Titan missile.

A Wind-Tunnel model of the Saturn I/Dyna-Soar combination [IMG: NASA]During 1961 there were a number of changes to the Saturn C-1s configuration but eventually a plan for Block I and Block II versions was reached to allow test flights to begin using the S-1 stage while development continued on the upper stages. Around this time thinking on the larger members of the Saturn family also changed with a new configuration, the three stage C-5 entering consideration. This huge booster would use five of the mighty F-1 engines in its first stage and would be capable of performing a Lunar Orbit Rendezvous (LOR) Moon landing mission with a single launch. Planners recognised that the C-5’s S-IVB third stage could be qualified for flight by using it as the second stage of a new C-1 configuration, the C-1B. As debate wore on within NASA as to which mode should be used to reach the Moon, development of the Block I Saturn C-1 continued apace at MSFC and the centre itself continued to grow taking in both the Michoud Assembly Facility in New Orleans, the Mississippi Test Facility and the Slidell Computer Facility. The physical size of the new booster required a different method of transport to previous ABMA vehicles. Whereas the Redstone and Jupiter could be transported by air or overland, for Saturn barges would be needed to move the S-1 stage from the gulf coast round to Cape Canaveral. This initially wasn’t a case of plain sailing though as the barge Compromise carrying the first S-1 stage ran aground a number of times.

A completed Block I Saturn S-1 stage [IMG: NASA]Test flights beginBy the summer of 1961 with initial static tests and design changes made at MSFC, the first Saturn was on its way to the cape where a new dedicated launch facility, Launch Complex 34 awaited it. Following a successful set of static tests the first Saturn I was ready to fly under the designation SA-1 (SA standing for Saturn – Apollo). As a Block I booster, this launch featured a live S-1 first stage but dummy S-IV and S-V stages and as such was intended as a suborbital test of the partially fuelled first stage only. On October 26 1961 SA-1 took to the Florida skies in a near perfect first mission impacting the Atlantic over 200 miles downrange. Considering the complex nature of the S-1 with its clustered tanks, engines and the copious plumbing needed to connect it all together SA-1 was an auspicious start to the age of Saturn.

SA-1 takes flight from LC-34 on October 26, 1961 [IMG: NASA]A second Block I flight, SA-2, followed in April 1962 and while this was for the most part a repeat of SA-1 it did conduct an interesting experiment in the form of Project Highwater. Dummy S-IV and S-V stages were again carried and contained water ballast to simulate the weight of the actual upper stages. When SA-2 reached its apogee at over 60 miles, explosive charges would be detonated to release the water into the upper ionosphere in the hope of creating atmospheric effects for observation from the ground. On April 26th SA-2 flew successfully and released its watery payload as planned creating a visible cloud and electrical disturbances which von Braun described as “probably the first synthetic thunderstorm ever generated in space.” Testing continued with SA-3 in November 1962, repeating the Highwater experiment and carrying a full load of propellant in the S-1 stage for the first time. The final Block I test, SA-4, took place on March 28th 1963 featuring a more exact aerodynamic representation of the S-IV stage and also testing the vehicle’s ability to deal with the failure of one of the H-1 engines. Again, this flight was a success and the cluster concept of the S-1 stage and the Saturn 1’s general design were now certified. It was time for Saturn to head for orbit.

SA-5 marked the first flight of the Block II variant of the Saturn I. For the first time a live second stage, the 6 engine hydrogen fuelled S-IV, would be carried. No actual payload was included on SA-5, again a Jupiter nosecone was carried in place of a third stage or Apollo spacecraft, but the two-stage Saturn was powerful enough to orbit the entire S-IV stage. SA-5 was also the first flight to carry an instrument unit above the S-IV to allow for the guidance and control of the rocket during ascent. It was also the first Saturn to carry the family’s characteristic tailfins to help with directional stability. The first launch attempt was made on January 27th 1964, but was scrubbed due to problems loading oxidiser into the S-1 stage. Things went more smoothly on the second attempt two days later and on the 29th January, SA-5 lifted off and headed downrange, placing the S-IV in an elliptical orbit but more importantly pushing NASA’s launch capabilities beyond those of the Soviets and clearing the way for tests of Apollo hardware to begin.

A Block II Saturn I launches [IMG: NASA]With the Block II version of the rocket now successfully tested, it was time to shift attention to the rocket’s payload and the sixth test flight, designated AS-101, carried a boilerplate Apollo capsule complete with launch escape system to test the aerodynamic performance of the complete stack. The mission launched on May 28th 1964 and successfully placed the boilerplate spacecraft in orbit. During initial ascent the S-1 first stage suffered an engine failure-the only H-1 failure of the program, but as had been proven during the flight of SA-4, the Saturn I was able to compensate by extending the burn of the remaining 7 engines. AS-102, the seventh Saturn I test, followed on September 18th again successfully orbiting a boilerplate Apollo spacecraft.

As 1965 dawned and attention turned to the imminent resumption of American crewed flights with the upcoming debut of the two-person Gemini, AS-103 became the first Saturn to carry a satellite into orbit. Again the Block II saturn I carried a boilerplate Apollo capsule, but the area that would have been occupied by the service module instead housed the Pegasus micrometeroid detection satellite. Pegasus featured a pair of 96 foot long extendable wings containing instrumentation to record the frequency and nature of meteroid impacts. The satellite remained attached to the spent S-IV stage giving the huge satellite a weight of nearly 4000 pounds. AS-103 launched on February 16 and, following separation of the boilerplate Apollo Command Module, Pegasus 1 was successfully deployed to orbit where it continued to gather valuable data for many years.

A second Pegasus satellite was carried by AS-104 which lifted off in the early hours of May 25th 1965 providing a spectacular nighttime launch. The S-1 stage for this ninth launch was the first not manufactured by the MSFC engineers, with production now turned over to Chrysler at the Michoud Assembly Facility. Chrysler had previously manufactured both the Redstone and Jupiter missiles designed by the Huntsville group, so they proved to be a natural fit for the S-1 stage which contained elements of both of the earlier designs.

AS-105 launched on July 30th carrying the third Pegasus satellite and marking the final flight of the original Saturn I series. All ten flights had gone largely as planned and those issues that had occurred were absorbed by the solid, conservative engineering which had come to characterise von Braun’s team. The clustering concept had been fully vindicated both in terms of the multi-engine and multi-tank configurations. While many of the Block II flights had provided initial support for Apollo by lifting boilerplate CMs and verifying the performance of the launch escape system, attention now turned to the upgraded Saturn 1B which would feature an improved S-1 first stage and the S-IVB second stage (under development as the third stage for the Saturn V) in place of the earlier S-IV.

Structure of the improved Saturn 1B [IMG: NASA]The Saturn 1BThe S-IVB, built like its predecessor by Douglas Aircraft, was powered by liquid hydrogen and used liquid oxygen oxidiser like the S-IV. Rather than the six smaller Centaur derived RL-10A-3 engines of the S-IV the new stage used a single large Rocketdyne J-2 engine, another product of the Silverstein Committee who had originally recommended cryogenically fuelled upper stages for the Saturn family. The S-IVB was considerably more powerful than the S-IV giving the Saturn 1B the capacity to lift a full weight Apollo spacecraft into orbit. Although broadly similar to the 500 Series version carried as the third stage on the Saturn V, the Saturn 1B’s 200 Series S-IVB didn’t need an on-orbit restart capability so carried less helium for tank pressurisation. It also featured a differently shaped adapter skirt as it was mated to the narrower S-1 stage. The Saturn 1B also carried an improved instrumentation unit built by IBM above the S-IVB and the larger Saturn V style fairing joining the second stage to the Apollo Service module.

The S-IVB Second Stage as carried on the Saturn 1B [IMG:NASA]The more powerful Saturn 1B would allow NASA to fly and qualify the Apollo Spacecraft, launching the uncrewed and initial crewed tests of the Block 1 CSM, but it also had another larger role planned. In response to a 1964 request by President Johnson for post-moon landing plans, the Future Programs Task Group was formed within NASA and recommended a programme of Earth and lunar orbital operations as well as the continued exploration of the lunar surface. These plans would utilise the hardware and techniques being developed for Apollo and subsequently became known as the Saturn-Apollo Applications (SAA) Program and later the Apollo Applications Program (AAP). By June 1966 two different schedules had been proposed covering both limited and full programmes to begin in 1968. In both cases the Saturn 1B was to play an important role with over 20 launches proposed, carrying both crews and materiel into orbit.

While plans for AAP continued to develop, the Saturn 1B reached flight status and on February 26th 1966 left the pad for the first time as AS-201 carrying the first Block I Apollo CSM. The new Saturn 1B worked perfectly allowing the Apollo Service Module engine to be tested in flight and the Block I Command Module to test re-entry procedures. Although some problems were encountered with the Apollo spacecraft, the flight was deemed to be generally successful. Delays with the next Block 1 spacecraft led to a change in flight sequence meaning AS-203 now flew in July 1966. No Apollo spacecraft was carried with the mission being predominantly focused on testing out the restart capabilities of the S-IVB needed for the upcoming lunar flights. AS-202 finally took place on August 25th as the final uncrewed test flight of the Block I Apollo CSM. As with AS-201 this was a suborbital test, but the Service Module engine was able to successfully demonstrate its restart capability and the Command Module performed a skip re-entry, a manoeuvre that would be vital for astronauts returning at high velocities from lunar missions. All was now set for the first crewed flight, AS-204 or as it is more commonly known Apollo 1.

Tragedy StrikesThe long delays with the Block I version of the Apollo spacecraft have been well documented but as AS-204 was prepared for flight it became increasingly obvious to many involved that the frenetic rush for the moon was leading to increased risks for the crew in a spacecraft that seemed far from complete or of an acceptable quality. With launch scheduled for February 21st 1967, crews struggled to complete the necessary preparations and simulations. On January 27th Astronauts Grissom, White and Chaffee entered the Command Module atop the unfueled Saturn 1B on Launch Complex 34 for what was to be a full ‘plugs-out’ test of the spacecraft under countdown conditions. During the test a flash fire though to have been started by a short-circuit in exposed wiring, occurred in the high pressure pure oxygen atmosphere and the crew, unable to extinguish the fire or escape the spacecraft due to the unwieldy inward opening hatch, were killed.

The tragedy shocked the country and caused seismic shocks within both NASA and congress leading to rigorous examination of the culture within the agency and its future plans. Following lengthy enquiries the Command Module underwent considerable redesign to improve quality and safety, but although the decision was made to honour Kennedy’s original target and push on towards a moon landing before the end of the decade, the repercussions of the AS-204 fire resulted in a curtailing of budgets for the follow-on Apollo Applications Program. Plans for a large ongoing production run for the Saturn boosters now disintegrated. Production would be limited to those boosters required to directly support the currently planned landings – von Braun’s dreams of creating a ‘DC-3’ for the space age seemed to lie in tatters.

Back on track for the moonAs the impact of budget cuts hit home there was still a job for the Saturn 1B to do in support of Apollo and that included the SA-204 booster that had sat below the inferno on that fateful day in January 1967. As the programme struggled to regain momentum following the investigations into the fire, the undamaged SA-204 was prepared for the first orbital test of the Lunar Module under the designation Apollo 5. Like the CSM, the Apollo Lunar Module had suffered a long series of delays as Grumman and the other LM contractors struggled to bring the spacecraft’s weight down and overcome problems with the engines. Finally on January 22nd 1968 Apollo 5 lifted off. No Apollo CSM was carried for this mission with a simple nose cone topping-off the fairing. The LM flew without legs and with aluminium plates replacing its windows following problems during pressurisation tests, but following separation from the S-IVB, the descent stage was fired several times followed by a firing of the ascent stage. The mission was slightly blighted by a programming error on the descent engine, but was generally regarded to have been successful.

The launch of the first crewed Apollo flight, Apollo 7, on October 1968 [IMG: NASA]The next Saturn 1B to fly would be SA-205 for the Apollo 7 mission. This was the first crewed flight of the Apollo programme and was a full orbital test of the redesigned and much improved Block II CSM. The mission launched on October 11th 1968 sending astronauts Schirra, Eisele and Cunningham on their 10-day 163 orbit test flight. Apollo 7 gave Schirra the unique honour of being the only astronaut to fly Mercury, Gemini and Apollo missions – a title that would surely have gone to Grissom had fate not intervened. Again the Saturn 1B performed flawlessly, but now the smaller of the Saturn family stepped out of the limelight as NASA managers took the bold decision to send Apollo 8 to lunar orbit atop the Saturn V in December 1968. There would be no more Saturn 1B flights in support of the Apollo moon landings but although it faced a long hiatus this was not the end of this rocket’s story.

A Taxi for SkylabThroughout the mid 1960s studies had been carried out into using elements of a Saturn V to create a space station. Understandably, von Braun was keen to develop new projects to ensure work for MSFC and suggested various configurations, some of which were examined further under AAP. As Apollo progressed and later moon landings were cancelled due to tightening budgets it looked likely that at least one Saturn V could now be spared to make plans for a large orbital incorporating some of the earlier space station plans and other Apollo Applications elements such as the Apollo Telescope Mount. Thus Skylab was born as a ‘dry workshop’ conversion of an S-IVB stage. Launched atop a Saturn V in May 1973, Skylab was visited by three crews each of whom launched in an Apollo CSM atop a Saturn 1B. In the event of an emergency another Saturn 1B was on standby to launch a rescue mission consisting of a modified Apollo CSM with a crew of two, but capable of returning five astronauts. Following the return of the third Skylab crew in February 1974, a short duration fourth crewed flight was considered using this booster. Skylab 5, as the mission would have been designated, would have boosted the station’s orbit prolonging its life but the mission was cancelled with hopes that a boost mission could be an early objective for the forthcoming Space Shuttle which NASA still aimed to be flying before the end of the decade.

Handshakes in SpaceFollowing the end of the Skylab programme, the Saturn 1B had one final mission to fly. The early 1970s saw a period of detente between the superpowers as President Nixon looked to improve American/Soviet relations following the end of the Vietnam War. This thaw in relations allowed for a joint flight between an Apollo and Soyuz to take place, ostensibly to test a universal docking adaptor that would allow Soviet and American ships to link up if required. The Apollo CSM would launch on a Saturn 1B with the large docking adaptor carried atop the S-IVB in the space previously reserved for Apollo Lunar Modules. The American side of the Apollo Soyuz Test Project launched on July 15th 1975 with a crew including Mercury 7 astronaut Deke Slayton who had remained grounded since the early 60s due to cardiac irregularities. The Apollo CSM rendezvoused and docked with Soyuz 19 two days later, remaining joined for nearly 2 days. Following undocking the American crew stayed in orbit until July 24th when they made the final, albeit troubled, splashdown of an Apollo spacecraft (during entry, toxic fumes from the ship’s RCS thrusters accidently entered the Command Module via an air intake temporarily incapacitating some of the crew and leading to a period of hospitalisation post-recovery). And so, following a career stretching back almost two decades to von Braun’s initial proposals to the Department of Defence, the age of the Saturn was over.

ConclusionsIt’s somehow fitting that the smaller Saturn 1B should be the last of the line to fly following a long and reliable career. No Saturn I (Block I or II) or 1B ever suffered a failure in flight beyond the single H-1 engine loss during AS-101. Born out of a hastily developed engineering compromise, the clustered tanks and eight engines of the S-1 stage proved remarkably reliable. The solid, conservative engineering and development methods of von Braun’s team at MSFC had been vindicated in spite of doubts from some quarters within NASA, but with MSFC’s attention now focused on the upcoming STS Shuttle programme it seemed that, for a while at least, the days of the large expandable space booster could be at an end. It’s interesting to contrast the development of the Saturn family with that other heavy-lift behemoth of the 1960s, the Soviet N-1 designed by Sergei Korolev’s OKB-1 bureau. Whereas the Saturn I and 1B allowed many of the components used on the Saturn V and the various Apollo spacecraft to be tested and verified, the N1 had its developmental siblings, the smaller N2 and N3 (and to a lesser extent the GR-1 Orbital Bombardment System) cancelled, thus putting all of the developmental pressure on the big rocket with disastrous consequences.

The huge industrial capability that had been created at Huntsville and its satellite centres such as Michoud remain a hugely important part of NASA, although not without their critics. Since the end of the Shuttle programme, first the Constellation and now the Space Launch System programmes have looked to re-use elements of shuttle-era hardware to create a new class of heavy launch vehicles. Strong congressional lobbies have ensured that work has continued to flow to the facilities originally created to support Saturn, but doubts about the practicality or requirement for a huge expensive rocket that can fly as infrequently as the SLS remain. To many it seems as if the main purpose of the new super-booster is more about retaining jobs and attempting to re-ignite a ‘spirit of Apollo’ rather than addressing America’s actual space needs for the coming decades.

FootnotesBeyond the activities mentioned above the Saturn I/1B was often brought into consideration for other programmes. During the development phases of the Titan II serious problems with longitudinal instability (pogo) were encountered. Although the resulting forces were considered acceptable by the Air Force for the missile’s military mission, they were felt too violent for a crew to tolerate during planned Gemini flights. For a short time during 1963 the Saturn I was considered as an alternative launcher for Gemini should efforts by Martin to tame Titan’s problems fail to produce an effective solution. Eventually a fix was found for the pogo problem, but in early 1964 a Saturn I/Gemini combination was again proposed, this time for a circumlunar flight in advance of the Apollo/Saturn V combination becoming available. These, along with the other various lunar Gemini plans came to nothing as managers within NASA reasonably concluded such an effort could prove a distraction and undermine the justification for Apollo.

Saturn I derived boosters were also considered in the late 1960s amongst a range of potential launchers for McDonnell Douglas’s proposed Big Gemini space station resupply vehicle, but again this came to nothing as a reusable winged shuttle became the preferred solution for this role as part of NASA’s Integrated Programme Plan.

Chrysler concept diagrams for MLV versions of the Saturn 1B featuring additional solid boosters [IMG: NASA]As part of a wider initiative during the mid 1960’s MSFC also examined ways of extending the utility of the whole Saturn family under the Modified Launch Vehicle (MLV) programme. A number of new configurations were examined for the Saturn 1B to increase its lifting capacity via the addition of existing solid rocket boosters from the Air Force Titan and Minutemen programmes. Had the AAP taken place as planned, some of these configurations may have seen the light of day but as it was with no extension of Saturn’s role envisioned following cuts to the FY 1968 budget, these designs went no further than the drawing board.

Stages of the Saturn S-1 parachute recovery concept circa 1961 [IMG: NASA]Interestingly one of the areas where Saturn looked to pioneer new technology was in the recovery and reusability of rocket stages. Even before the move to NASA, von Braun had recognised that the economies reusability could provide would be advantageous if the Saturn I was really to achieve the high flight rates he hoped for. In 1961 studies were commissioned by both Ryan and North American to investigate the recovery of the S-1 stage with both parachute and deployable wings considered. In the latter case this involved the use of the Rogallo wing which would later become more famous for its planned inclusion on the Gemini spacecraft. The Rogallo wing would have allowed the S-1 stage to make horizontal landings on a prepared strip at Cape Canaveral. Parachute recovery would have meant landing the stage vertically at sea, then towing it back to land for refurbishment. Saltwater immersion tests on the H-1 engine were carried out with promising results but given time and budget constraints the plans for recovery of the S-1 were sadly dropped by the time the stage went into production.